import imgPath from "./sakuraImg";

var stop, staticx;
var img = new Image();
img.src = imgPath;

function Sakura(x, y, s, r, fn) {
    this.x = x;
    this.y = y;
    this.s = s;
    this.r = r;
    this.fn = fn;
}

Sakura.prototype.draw = function (cxt) {
    cxt.save();
    // var xc = (40 * this.s) / 4;
    cxt.translate(this.x, this.y);
    cxt.rotate(this.r);
    cxt.drawImage(img, 0, 0, 40 * this.s, 40 * this.s);
    cxt.restore();
};
Sakura.prototype.update = function () {
    this.x = this.fn.x(this.x, this.y);
    this.y = this.fn.y(this.y, this.y);
    this.r = this.fn.r(this.r);
    if (
        this.x > window.innerWidth ||
        this.x < 0 ||
        this.y > window.innerHeight ||
        this.y < 0
    ) {
        this.r = getRandom("fnr");
        if (Math.random() > 0.4) {
            this.x = getRandom("x");
            this.y = 0;
            this.s = getRandom("s");
            this.r = getRandom("r");
        } else {
            this.x = window.innerWidth;
            this.y = getRandom("y");
            this.s = getRandom("s");
            this.r = getRandom("r");
        }
    }
};
var SakuraList = function () {
    this.list = [];
};
SakuraList.prototype.push = function (sakura) {
    this.list.push(sakura);
};
SakuraList.prototype.update = function () {
    for (var i = 0, len = this.list.length; i < len; i++) {
        this.list[i].update();
    }
};
SakuraList.prototype.draw = function (cxt) {
    for (var i = 0, len = this.list.length; i < len; i++) {
        this.list[i].draw(cxt);
    }
};
SakuraList.prototype.get = function (i) {
    return this.list[i];
};
SakuraList.prototype.size = function () {
    return this.list.length;
};

function getRandom(option) {
    var ret, random;
    switch (option) {
        case "x":
            ret = Math.random() * window.innerWidth;
            break;
        case "y":
            ret = Math.random() * window.innerHeight;
            break;
        case "s":
            ret = Math.random();
            break;
        case "r":
            ret = Math.random() * 6;
            break;
        case "fnx":
            random = -0.5 + Math.random() * 1;
            ret = function (x, y) {
                return x + 0.5 * random - 1.7;
            };
            break;
        case "fny":
            random = 1.5 + Math.random() * 0.7;
            ret = function (x, y) {
                return y + random;
            };
            break;
        case "fnr":
            random = Math.random() * 0.03;
            ret = function (r) {
                return r + random;
            };
            break;
        default:
            ret = Math.random();
    }
    return ret;
}

function startSakura(domId, numbers) {
    var requestAnimationFrame =
        window.requestAnimationFrame ||
        window.mozRequestAnimationFrame ||
        window.webkitRequestAnimationFrame ||
        window.msRequestAnimationFrame ||
        window.oRequestAnimationFrame;
    var canvas = document.createElement("canvas"),
        cxt;
    staticx = true;
    canvas.height = window.innerHeight;
    canvas.width = window.innerWidth;
    // 此处去掉了默认样式
    // canvas.setAttribute(
    //   'style',
    //   'position: fixed;left: 0;top: 0;pointer-events: none;'
    // );
    canvas.setAttribute("id", "canvas_sakura");
    domId.appendChild(canvas);
    cxt = canvas.getContext("2d");
    var sakuraList = new SakuraList();
    for (var i = 0; i < numbers; i++) {
        var sakura,
            randomX,
            randomY,
            randomS,
            randomR,
            randomFnx,
            randomFny,
            randomFnR;
        randomX = getRandom("x");
        randomY = getRandom("y");
        randomR = getRandom("r");
        randomS = getRandom("s");
        randomFnx = getRandom("fnx");
        randomFny = getRandom("fny");
        randomFnR = getRandom("fnr");
        sakura = new Sakura(randomX, randomY, randomS, randomR, {
            x: randomFnx,
            y: randomFny,
            r: randomFnR,
        });
        sakura.draw(cxt);
        sakuraList.push(sakura);
    }
    stop = requestAnimationFrame(function p() {
        cxt.clearRect(0, 0, canvas.width, canvas.height);
        sakuraList.update();
        sakuraList.draw(cxt);
        // avoid arguments.callee
        // stop = requestAnimationFrame(arguments.callee);
        stop = requestAnimationFrame(p);
    });
}

window.onresize = function () {
    // var canvasSnow = document.getElementById('canvas_snow');
};

function stopp(domId, numbers) {
    if (staticx) {
        var child = document.getElementById("canvas_sakura");
        child.parentNode.removeChild(child);
        window.cancelAnimationFrame(stop);
        staticx = false;
    } else {
        startSakura(domId, numbers);
    }
}

// img.onload = function () {
//   staticx = false;
//   stopp();
// };

/**
 * 配置参数
 * @id String . cavas渲染的父容器的css id，默认是body
 * @numbers Number . 花瓣个数
 */
export function init(o) {
    var _o = o || {};
    var domId = _o.id ? document.getElementById(_o.id) : document.body;
    var numbers = _o.numbers || 50;
    staticx = false;
    stopp(domId, numbers);
}
